From 95f22c53059ccd60ee701ccf2659dacd95e4e89a Mon Sep 17 00:00:00 2001
From: Tommi Hirvola <tommi@hirvola.fi>
Date: Mon, 4 Mar 2024 12:56:30 +0200
Subject: [PATCH] set upper limit for REP escape sequence argument
Previously, printf 'L\033[2147483647b' would call tputc('L') 2^31 times,
making st unresponsive. This commit allows repeating the last character
at most 65535 times in order to prevent freezing and DoS attacks.
---
st.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/st.c b/st.c
index 77c3e8a..683493d 100644
--- a/st.c
+++ b/st.c
@@ -1643,7 +1643,7 @@ csihandle(void)
ttywrite(vtiden, strlen(vtiden), 0);
break;
case 'b': /* REP -- if last char is printable print it <n> more times */
- DEFAULT(csiescseq.arg[0], 1);
+ LIMIT(csiescseq.arg[0], 1, 65535);
if (term.lastc)
while (csiescseq.arg[0]-- > 0)
tputc(term.lastc);